Leto's mother is Phoebe; her sister, Asterie. Sometimes Hekate is named a sister, too. Hesiod presents Leto as "gentle to men and gods".
Leto's delivery of her children was problematic because their father was Zeus and Zeus' wife Hera was jealous. The childbirth goddess Eileitheia arrived days late -- having been delayed deliberately by Hera. By the time of Eileitheia's arrival, Leto was 9 days into her labor and on the island of Delos. Persuading rocky Delos to allow Leto to give birth had been difficult. All the possible locations were reluctant to accept Leto because it would mean risking Hera's wrath, but Delos agreed on certain terms. It required an oath on the River Styx that Leto's children would pay it honors. With the oath delivered, the island Delos acquiescent, and the childbirth goddess' help, Leto gave birth to her children (or Artemis was born on Ortygia and only Apollo on Delos), leaning on Mt. Cynthos.
In Greek art, Leto is shown with her children, mounting a chariot, or abducted by Tityos with or without an arrow in his head. Leto has a minor role in the Iliad.
Reference: Timothy Gantz Early Greek Myth.
Leto may be one of the characters depicted on the Corbridge Lanx.
